JP2018090431A - Nickel cobalt manganese composite hydroxide, method for producing nickel cobalt manganese composite hydroxide, and lithium metal composite oxide particle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a nickel cobalt manganese composite hydroxide serving as a precursor of a positive electrode active material that in use for a lithium ion secondary battery, allows the lithium ion secondary battery to have a high output.SOLUTION: Provided are nickel cobalt manganese composite hydroxide particles represented by the general formula: NiCoMnM(OH), where x+y+z+t=1, 0.05≤x≤0.3, 0.1≤y≤0.4, 0.6≤z≤0.8, 0≤t≤0.1, 0≤a≤0.5, and M is one or more kinds of additive elements selected from Mg, Ca, Al, Ti, V, Cr, Zr, Nb, Mo and W. Secondary particles of the nickel cobalt manganese composite hydroxide particles have a structure of agglomerated primary particles which are composed of needle plate-shaped crystals.SELECTED DRAWING: Figure 1

Description

  The present invention relates to nickel cobalt manganese composite hydroxide, a method for producing nickel cobalt manganese composite hydroxide, and lithium metal composite oxide particles.

  In recent years, with the widespread use of portable electronic devices such as mobile phones and notebook computers, development of small and light non-aqueous electrolyte secondary batteries having high energy density is strongly desired.

  In addition, development of a high output secondary battery is strongly desired as a large battery such as a motor drive power source.

  As a secondary battery satisfying such requirements, there is a lithium ion secondary battery. A lithium ion secondary battery includes a negative electrode, a positive electrode, an electrolytic solution, and the like, and a material capable of desorbing and inserting lithium is used as an active material of the negative electrode and the positive electrode.

  Research and development of lithium-ion secondary batteries are currently underway. Among them, a lithium ion secondary battery using a layered or spinel type lithium metal composite oxide as a positive electrode material can be used as a battery having a high energy density because a high voltage of 4V can be obtained.

As a positive electrode material of the lithium ion secondary battery, lithium cobalt composite oxide (LiCoO ₂ ), which is currently relatively easy to synthesize, lithium nickel composite oxide (LiNiO ₂ ) using nickel cheaper than cobalt, lithium Nickel cobalt manganese composite oxide (LiNi _1/3 Co _1/3 Mn _1/3 O ₂ ), lithium manganese composite oxide (LiMn ₂ O ₄ ) using manganese, lithium nickel manganese composite oxide (LiNi _0.5 Mn _0.5 O _2), lithium-rich nickel-cobalt-manganese composite oxide _{(Li 2 MnO 3 -LiNi X Mn} y Co z O 2) lithium composite oxide such as have been proposed.

Among these positive electrode active materials, in recent years, lithium has excellent thermal stability over a nickel-cobalt-manganese composite oxide _{(Li 2 MnO 3 -LiNi x Mn} y Co z O 2) has attracted attention in a high capacity. The lithium-excess nickel-cobalt-manganese composite oxide is a layered compound like the lithium-cobalt composite oxide and the lithium-nickel composite oxide (see Non-Patent Document 1).

  And the manufacturing method of the precursor for obtaining the lithium excess nickel cobalt manganese complex oxide is disclosed by patent document 1 and patent document 2, for example.

  Incidentally, in recent years, there has been a demand for higher output for lithium ion secondary batteries. In order to increase the output of the lithium ion secondary battery, it is considered necessary to optimize the internal structure of the positive electrode active material particles.

JP2011-028999A JP 2011-146392 A

FB Technical News, No.66, 2011.1

  However, in Patent Documents 1 and 2, the lithium nickel cobalt manganese composite oxide finally obtained and the production method thereof have been studied for the crystal structure of the obtained particle, but the structure of the obtained particle is particularly referred to. It has not been. In particular, the internal structure and battery characteristics of secondary particles have not been studied.

  Accordingly, in view of the above-described problems of the prior art, in one aspect of the present invention, a nickel-cobalt-manganese composite hydroxide serving as a precursor of a positive electrode active material capable of achieving high output in the case of a lithium ion secondary battery. The purpose is to provide.

In order to solve the above problems, according to one aspect of the present invention,
General formula: Ni _x Co _y Mn _z M _t (OH) _{2 + a} (x + y + z + t = 1, 0.05 ≦ x ≦ 0.3, 0.1 ≦ y ≦ 0.4, 0.6 ≦ z ≦ 0.8, 0 ≦ t ≦ 0.1, 0 ≦ a ≦ 0.5, M is one or more additive elements selected from Mg, Ca, Al, Ti, V, Cr, Zr, Nb, Mo, and W) Nickel cobalt manganese composite hydroxide particles represented,
The secondary particles of the nickel cobalt manganese composite hydroxide particles provide nickel cobalt manganese composite hydroxide particles having a structure in which primary particles composed of needle plate crystals are aggregated.

  According to one embodiment of the present invention, a nickel-cobalt-manganese composite hydroxide serving as a precursor of a positive electrode active material that can achieve high output when a lithium ion secondary battery is used can be provided.

The flowchart of the crystallization process in the manufacturing method of the nickel cobalt manganese composite hydroxide particle which concerns on embodiment of this invention. The cross-sectional block diagram of the non-aqueous electrolyte secondary battery produced by the Example and the comparative example.

DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings. However, the present invention is not limited to the following embodiments, and the following embodiments are not departed from the scope of the present invention. Various modifications and substitutions can be made.
[Nickel cobalt manganese composite hydroxide]
First, one structural example of the nickel cobalt manganese composite hydroxide particles of the present embodiment will be described.

The nickel-cobalt-manganese composite hydroxide particles of the present embodiment have a general formula: Ni _x Co _y Mn _z M _t (OH) _{2 + a} (x + y + z + t = 1, 0.05 ≦ x ≦ 0.3, 0.1 ≦ y ≦ 0.4, 0.6 ≦ z ≦ 0.8, 0 ≦ t ≦ 0.1, 0 ≦ a ≦ 0.5, M is Mg, Ca, Al, Ti, V, Cr, Zr, Nb, Mo , One or more additive elements selected from W) particles of nickel cobalt manganese composite hydroxide.

  And the secondary particle of nickel cobalt manganese composite hydroxide particle can have the structure where the primary particle comprised from a needle-plate-like crystal aggregated.

  The inventor of the present invention diligently studied a positive electrode active material capable of achieving high output of a lithium ion secondary battery. As a result, it has been found that it is effective to use a positive electrode active material having uniform pores inside the particles because it is effective to shorten the moving distance between positive and negative electrodes of lithium ions. Then, it has been found that a positive electrode active material having uniform pores inside the particles can be obtained by using a positive electrode active material precursor having a predetermined structure, that is, nickel cobalt manganese composite hydroxide particles. Was completed.

  The nickel cobalt manganese composite hydroxide particles of the present embodiment are particles of a hydroxide type nickel cobalt manganese composite. The nickel-cobalt-manganese composite hydroxide particles of the present embodiment have a needle plate-like crystal of primary particles, and secondary particles can be constituted by the primary particles. That is, the primary particles can be aggregated to form secondary particles. The needle plate shape means a plate shape that narrows from one end to the other end.

  The secondary particles of the nickel cobalt manganese composite hydroxide particles of the present embodiment have a structure, so that the positive electrode active material is generated using the nickel cobalt manganese composite hydroxide particles of the present embodiment as the positive electrode active material precursor. In this case, a positive electrode active material having uniform pores inside the particles can be obtained.

The nickel-cobalt-manganese composite hydroxide particles of the present embodiment have a general formula: Ni _x Co _y Mn _z M _t (OH) _{2 + a} (x + y + z + t = 1, 0.05 ≦ x ≦ 0.3, 0.1 ≦ y ≦ 0.4, 0.6 ≦ z ≦ 0.8, 0 ≦ t ≦ 0.1, 0 ≦ a ≦ 0.5, M is Mg, Ca, Al, Ti, V, Cr, Zr, Nb, Mo , One or more additive elements selected from W) and nickel cobalt manganese composite hydroxide particles.

  The nickel-cobalt-manganese composite hydroxide particles of the present embodiment can be particles containing the nickel-cobalt-manganese composite hydroxide represented by the above general formula, but are particularly represented by the above general formula. The particles are preferably composed of nickel cobalt manganese composite hydroxide. However, even in the case of particles composed of the nickel cobalt manganese composite hydroxide represented by the above general formula, it is not excluded that, for example, inevitable components mixed in the manufacturing process are included.

Furthermore, in the nickel-cobalt composite hydroxide particles of the present embodiment, elements other than nickel, cobalt, and manganese are uniformly distributed inside the secondary particles and / or the surface of the secondary particles is uniformly coated. Is preferred.
[Method for producing nickel cobalt manganese composite hydroxide particles]
Next, a configuration example of the method for producing nickel cobalt manganese composite hydroxide particles of the present embodiment will be described.

The manufacturing method of the nickel cobalt manganese composite hydroxide particles of the present embodiment has a general formula: Ni _x Co _y Mn _z M _t (OH) _{2 + a} (x + y + z + t = 1, 0.05 ≦ x ≦ 0.3, 0.1 ≦ y ≦ 0.4, 0.6 ≦ z ≦ 0.8, 0 ≦ t ≦ 0.1, 0 ≦ a ≦ 0.5, M is Mg, Ca, Al, Ti, V, Cr, Zr, 1) One or more additive elements selected from Nb, Mo, and W), and a method for producing nickel cobalt manganese composite hydroxide particles represented by the following crystallization step.

  A crystallization step of mixing a mixed aqueous solution containing a nickel-containing compound, a cobalt-containing compound, and a manganese-containing compound with an initial aqueous solution containing an alkaline aqueous solution to form a reaction aqueous solution in an oxygen-containing gas atmosphere. .

  A configuration example of a method for producing nickel cobalt manganese composite hydroxide particles of the present embodiment will be described with reference to FIG.

As shown in FIG. 1, the method for producing nickel cobalt manganese composite hydroxide particles of the present embodiment can include a crystallization step, and the crystallization step includes, for example, a nucleation step and a particle growth step. Can have. This will be described below separately for the nucleation step and the particle growth step.
(Crystallization process)
a) Nucleation Step First, the nucleation step will be described with reference to FIG.

  As shown in FIG. 1, first, a nickel-containing compound (metal compound), a cobalt-containing compound (metal compound), and a manganese-containing compound (metal compound) are dissolved in water at a predetermined ratio and mixed. An aqueous solution can be made.

  Each metal compound is not particularly limited, but a water-soluble metal compound is preferably used, and examples of the water-soluble metal compound include nitrates, sulfates, hydrochlorides and the like. Specifically, for example, nickel sulfate, cobalt sulfate, manganese sulfate and the like can be suitably used.

  In the method for producing nickel cobalt manganese composite hydroxide particles of the present embodiment, the composition ratio of each metal in the obtained nickel cobalt manganese composite hydroxide particles is almost the same as the composition ratio of each metal in the mixed aqueous solution. Therefore, the ratio of the metal compound dissolved in water so that the composition ratio of each metal in the mixed aqueous solution is the same as the target composition ratio of each metal in the nickel cobalt manganese composite hydroxide particles of the present embodiment. Can be adjusted to produce a mixed aqueous solution.

  In addition, as shown with the dotted line in FIG. 1, the compound aqueous solution can also be mixed by mixing the compound containing 1 or more types of additional elements in a predetermined ratio as needed.

  Specifically, the compound containing an additive element is a water-soluble compound containing one or more additive elements selected from Mg, Ca, Al, Ti, V, Cr, Zr, Nb, Mo, and W. Preferably used, for example, titanium sulfate, ammonium peroxotitanate, potassium oxalate, vanadium sulfate, ammonium vanadate, chromium sulfate, potassium chromate, zirconium sulfate, zirconium nitrate, niobium oxalate, ammonium molybdate, tungstic acid One or more selected from sodium, ammonium tungstate, and the like can be used.

  Thus, by adding the compound containing an additional element to the mixed aqueous solution, the additive element can be co-precipitated in a state of being uniformly dispersed inside the nickel cobalt manganese composite hydroxide particles. For this reason, the core of the nickel cobalt manganese composite hydroxide in which the additive element is uniformly dispersed is obtained.

  The total concentration of the above-mentioned metal compound in the mixed aqueous solution, that is, the compound containing nickel, the compound containing cobalt, the compound containing manganese, and the compound containing an additive element is not particularly limited, and is arbitrary. Can be selected. For example, the total concentration of the above-described metal compounds in the mixed aqueous solution is preferably 1.0 mol / L or more and 2.6 mol / L or less. In particular, the total concentration of the metal compounds in the mixed aqueous solution is more preferably 1.5 mol / L or more and 2.2 mol / L or less.

  This is because, by setting the total concentration of the above-described metal compounds in the mixed aqueous solution to 1.0 mol / L or more, the amount of crystallized matter per reaction tank can be sufficiently secured, and productivity can be increased. It is. However, if the total concentration of the above-mentioned metal compounds in the mixed aqueous solution exceeds 2.6 mol / L, the saturation concentration at room temperature may be exceeded, and there is a risk of crystals re-depositing and clogging the equipment piping. Therefore, it is preferably 2.6 mol / L or less.

  In addition, the above-mentioned metal compound does not necessarily need to be mixed aqueous solution. For example, by mixing a plurality of metal compounds, when specific metal compounds react with each other to generate an unnecessary compound, an aqueous solution containing the metal compounds can be individually prepared. And you may add simultaneously the aqueous solution containing each prepared metal compound to the initial stage aqueous solution and nucleation reaction aqueous solution which are mentioned later in a predetermined ratio. In this case, it is preferable to adjust and add such that the concentration of the total metal compounds in the aqueous solution containing the individually added metal compounds is within the above-described concentration range of the mixed aqueous solution.

  On the other hand, an initial aqueous solution can be prepared by supplying and mixing an alkaline aqueous solution such as an aqueous sodium hydroxide solution and water into the reaction vessel. It should be noted that an aqueous ammonia solution containing an ammonium ion supplier can also be added to the initial aqueous solution.

  The alkali aqueous solution is not particularly limited, and for example, an alkali metal hydroxide aqueous solution containing one or more selected from alkali metal hydroxides such as sodium hydroxide and potassium hydroxide can be used.

  In addition, although it does not specifically limit as an ammonium ion supply body, For example, 1 or more types selected from ammonium carbonate aqueous solution, ammonia water, ammonium chloride aqueous solution, ammonium sulfate aqueous solution can be used preferably.

  When adjusting the initial aqueous solution (pre-reaction aqueous solution), the amount of each component to be added is not particularly limited, but the amount of the alkaline aqueous solution added is 11. It is preferable to adjust so that it may become 0 or more and 13.0 or less, and it is more preferable to adjust so that it may become 11.0 or more and 12.5 or less.

  The concentration of ammonium ions in the initial aqueous solution is preferably 0 or more and 15 g / L or less, and more preferably 5 g / L or more and 10 g / L or less. For this reason, for example, it is preferable to adjust the ammonium ion concentration in the initial aqueous solution by adjusting the addition amount of the aqueous ammonia solution as described above.

  In addition, although the temperature (liquid temperature) of initial stage aqueous solution is not specifically limited, For example, it is preferable that it is 20 to 60 degreeC, and it is more preferable that it is 30 to 50 degreeC.

  Then, after preparing the initial aqueous solution in the reaction vessel, the mixed aqueous solution can be added to the initial aqueous solution while stirring the initial aqueous solution.

  By adding and mixing the mixed aqueous solution to the initial aqueous solution, a nucleation reaction aqueous solution that is a reaction aqueous solution in the nucleation step is formed, and fine nuclei of nickel cobalt manganese composite hydroxide are generated in the nucleation reaction aqueous solution. The

  In addition, in the nucleation step, when the mixed aqueous solution is added to the initial aqueous solution to generate particle nuclei, the pH value of the nucleation reaction aqueous solution and the concentration of ammonium ions change with the nucleation. For this reason, alkaline aqueous solution and ammonia aqueous solution can also be added to nucleation reaction aqueous solution with mixed aqueous solution as needed.

  When an alkaline aqueous solution is added to adjust the pH in the aqueous nucleation reaction solution, the alkaline aqueous solution to be added is not particularly limited, and examples thereof include alkali metal hydroxides such as sodium hydroxide and potassium hydroxide. An alkali metal hydroxide aqueous solution containing one or more selected from those can be used. The same alkaline aqueous solution as that used when preparing the initial aqueous solution can also be used.

  In addition, when adjusting pH of nucleation reaction aqueous solution, it can replace with the above-mentioned alkaline aqueous solution, and can also add an alkali compound, for example, an alkali metal hydroxide, directly to nucleation reaction aqueous solution, without making aqueous solution. However, from the viewpoint of easy pH control of the aqueous nucleation reaction solution, the alkali compound is preferably dissolved in water and added as an aqueous solution to the aqueous nucleation reaction solution in the reaction vessel.

  The aqueous ammonia solution is not particularly limited, and an aqueous solution of one or more ammonium donors selected from the same ammonium donors as exemplified in the initial aqueous solution can be used.

  The pH value (set pH value) of the nucleation reaction aqueous solution is preferably maintained in the same range as the above-mentioned initial aqueous solution, that is, in the range of 11.0 or more and 13.0 or less on the basis of the liquid temperature of 40 ° C. In particular, the pH value of the aqueous nucleation reaction solution is more preferably maintained in the range of 11.0 or more and 12.5 or less on the 40 ° C. standard. This is because, during the nucleation reaction step, by maintaining the pH value of the nucleation reaction aqueous solution in the above range, the produced nuclei hardly grow and the nucleation occurs preferentially.

  Further, in the nucleation reaction step, from the viewpoint of generating nuclei of uniform size, it is preferable to suppress the fluctuation range of the pH value of the nucleation reaction aqueous solution, and the fluctuation range of the pH value of the nucleation reaction aqueous solution is the set pH value. It is preferably within ± 0.1, and more preferably within a set pH value of ± 0.05.

  The concentration of ammonium ions in the nucleation reaction aqueous solution (set ammonium ion concentration) is also preferably controlled so as to be maintained at the same concentration as that of the above-mentioned initial aqueous solution, that is, from 0 to 15 g / L, from 5 g / L to 10 g / L. It is more preferable to control to maintain the following.

  In the nucleation step, the ammonium ion concentration in the aqueous nucleation reaction solution preferably has a small fluctuation range, more preferably constant. This is because if the ammonium ion concentration in the aqueous nucleation reaction solution fluctuates, the solubility of metal ions in the aqueous solution will fluctuate, which may hinder the formation of nuclei of uniform nickel cobalt manganese composite hydroxide particles. It is.

  In the nucleation step, the ammonium ion concentration in the aqueous nucleation reaction solution is preferably, for example, within a set ammonium ion concentration ± 2.0 g / L, and more preferably within a set ammonium ion concentration ± 1.0 g / L. preferable.

  By supplying a mixed aqueous solution, and further, if necessary, an alkaline aqueous solution or an aqueous ammonia solution to the nucleation reaction aqueous solution, new nuclei are continuously generated in the nucleation reaction aqueous solution.

  The method of adding the mixed aqueous solution, the alkaline aqueous solution, or the aqueous ammonia solution to the initial aqueous solution in the reaction tank or the nucleation reaction aqueous solution is not particularly limited, and can be added by any method. For example, if the initial aqueous solution or the nucleation reaction aqueous solution is sufficiently stirred, a flow rate control pump such as a metering pump can be added so that the pH value of the nucleation reaction aqueous solution is maintained within a predetermined range. Good.

  The temperature of the aqueous nucleation reaction solution is not particularly limited, but it is preferably maintained at 20 ° C. or higher and 60 ° C. or lower, more preferably 30 ° C. or higher and 50 ° C. or lower during the nucleation step. This is preferable because the temperature of the nucleation reaction aqueous solution is set to 20 ° C. or more and 60 ° C. or less, and the energy for heating the nucleation reaction aqueous solution can be suppressed to the minimum while the nucleation reaction proceeds sufficiently. Because.

  Then, when a predetermined amount of nuclei is generated in the aqueous nucleation reaction solution, the nucleation step can be completed. Whether or not a predetermined amount of nuclei has been generated can be determined by the amount of metal salt added to the aqueous nucleation reaction solution.

  In the method for producing nickel cobalt manganese composite hydroxide particles of the present embodiment, the crystallization step is preferably performed in an oxygen-containing gas atmosphere.

  Therefore, in the nucleation step, it is preferable to supply the mixed aqueous solution after the atmosphere is controlled by blowing an oxygen-containing gas, for example, air, into the reaction tank in which the initial aqueous solution is prepared. Further, air can be continuously blown in while supplying the mixed aqueous solution. In this way, by adding the mixed aqueous solution to the initial aqueous solution in an oxygen-containing gas atmosphere, it reacts with dissolved oxygen contained in the resulting nucleation reaction aqueous solution or oxygen contained in the supplied air, etc. Core particles of nickel-cobalt-manganese composite hydroxide, which is a source of crystal particles, are generated.

  Since dissolved oxygen in the nucleation reaction aqueous solution is consumed during the nucleation reaction, whether the supply amount of the oxygen-containing gas is sufficient can be confirmed by measuring the dissolved oxygen concentration in the nucleation reaction aqueous solution. If the amount of dissolved oxygen in the nucleation reaction aqueous solution is more than half of the saturation amount, sufficient dissolved oxygen is present in the reaction, and oxygen can be sufficiently supplied. On the other hand, if the dissolved oxygen amount in the nucleation reaction aqueous solution is less than half of the saturation amount, the dissolved oxygen amount in the nucleation reaction aqueous solution may not be sufficient, so the supply amount of the oxygen-containing gas is increased. It is preferable.

The pH value, ammonium ion concentration, and dissolved oxygen amount in the aqueous nucleation reaction solution can be measured with a general pH meter, ion meter, and dissolved oxygen meter, respectively.
b) Particle Growth Step Next, the particle growth step will be described with reference to FIG.

  As shown in FIG. 1, in the particle growth step, a pH-adjusted nucleation reaction aqueous solution adjusted so that the pH value of the nucleation reaction aqueous solution obtained in the nucleation step is within a predetermined range can be prepared. Thereafter, the mixed aqueous solution can be added to the aqueous nucleation reaction solution after pH adjustment. In addition, when adding mixed aqueous solution, in order to adjust and maintain the pH value and ammonium ion density | concentration of the particle growth reaction aqueous solution obtained, alkaline aqueous solution, ammonia aqueous solution, etc. can also be added together.

  As will be described later, in the particle growth step, the pH value of the particle growth reaction aqueous solution is preferably 10.0 or more and less than 11.0. Therefore, the pH value of the nucleation reaction aqueous solution after the pH adjustment is preferably adjusted to be 10.0 or more and less than 11.0 on the basis of the liquid temperature of 40 ° C. as in the particle growth step. It is more preferable to adjust so that it may become less than 11.0. The solution used for adjusting the pH value is not particularly limited. For example, an acidic material can be used, and sulfuric acid, hydrochloric acid, or an aqueous solution thereof can be used. In addition, it is preferable that parameters other than pH of the nucleation reaction aqueous solution after pH adjustment, that is, temperature (liquid temperature) and ammonium ion concentration are within the range described in the nucleation reaction step.

  In the particle growth step, a mixed aqueous solution or, if necessary, an aqueous alkaline solution, an aqueous ammonia solution, or the like can be added to the nucleation reaction aqueous solution after pH adjustment as described above.

  In the particle growth step, the pH value (set pH value) of the particle growth reaction aqueous solution is preferably 10.0 or more and less than 11.0, more preferably 10.5 or more and less than 11.0, based on 40 ° C. preferable. By setting the pH value of the aqueous solution for nuclear growth reaction to less than 11.0, it is preferable because the particle growth reaction can be sufficiently advanced, and the residue of impurity cations in the crystallized product can be particularly suppressed. Further, it is preferable to set the pH value of the particle growth reaction aqueous solution to 10.0 or more, because the impurity anions can be particularly suppressed from remaining in the crystallized product.

  Therefore, in the particle growth step, by setting the pH value of the particle growth reaction aqueous solution within the above range, nickel cobalt manganese composite hydroxide particles with a small amount of remaining impurities can be obtained while sufficiently promoting the particle growth reaction. it can.

  The method for controlling the pH value of the particle growth reaction aqueous solution is not particularly limited. For example, the pH value can be controlled by adding an alkaline aqueous solution to the particle growth reaction aqueous solution and adjusting the addition amount.

  In addition, lithium ion secondary batteries using a positive electrode active material with a wide particle size distribution select the particles of the positive electrode material when charging and discharging are repeated due to non-uniform voltage applied to the particles in the electrode. May deteriorate and the capacity may decrease. And normally, the particle size distribution of a positive electrode active material has inherited the characteristic of the particle size distribution of the positive electrode active material precursor used when producing | generating this positive electrode active material. For this reason, it is preferable that the nickel cobalt manganese composite hydroxide particles of the present embodiment that can be used as the positive electrode active material precursor have a narrow particle size distribution. And, according to the study of the inventors of the present invention, in the particle growth process, by suppressing the fluctuation range of the pH value of the particle growth reaction aqueous solution, the width of the particle size distribution of the obtained nickel cobalt manganese composite hydroxide particles is reduced. Can be suppressed. For this reason, it is preferable to suppress the fluctuation range of the pH value of the particle growth reaction aqueous solution. For example, in the particle growth process, the fluctuation range of the pH value of the particle growth reaction aqueous solution may be within the set pH value ± 0.1. Preferably, the set pH value is within ± 0.05.

  Further, the ammonium ion concentration (set ammonium ion concentration) in the particle growth reaction aqueous solution is not particularly limited. For example, it is preferably controlled to be maintained at 0 or more and 15 g / L or less, and preferably 5 g / L or more and 10 g / L. It is more preferable to control to maintain the following.

  This is because it is preferable that the ammonium ion concentration in the particle growth reaction aqueous solution be 0 or more and 15 g / L or less because the nuclei of nickel cobalt manganese composite hydroxide particles can be grown particularly uniformly.

  As described above, in the nucleation step and the particle growth step, that is, in the crystallization step, the ammonium ion concentration in the initial aqueous solution and in the reaction aqueous solution obtained by mixing the initial aqueous solution and the mixed aqueous solution is 0 or more and 15 g / L or less is preferable. In particular, the ammonium ion concentration in the initial aqueous solution and the reaction aqueous solution is more preferably 5 g / L or more and 10 g / L or less. The reaction aqueous solution means the nucleation reaction aqueous solution and the particle growth reaction aqueous solution described above, and includes the nucleation reaction aqueous solution after pH adjustment. Hereinafter, the reaction aqueous solution is used to indicate both the nucleation reaction aqueous solution, the pH-adjusted nucleation reaction aqueous solution, and the particle growth reaction aqueous solution.

  In the particle growth step, the fluctuation range of the ammonium ion concentration in the particle growth reaction aqueous solution is preferably small, and more preferably constant. This is because if the concentration of ammonium ions in the aqueous solution for particle growth varies, the solubility of metal ions in the aqueous solution will vary, and the growth of nuclei of uniform nickel cobalt manganese composite hydroxide particles may be hindered. It is.

  In the particle growth process, the ammonium ion concentration in the particle growth reaction aqueous solution is preferably, for example, within a set ammonium ion concentration ± 2.0 g / L, and more preferably within a set ammonium ion concentration ± 1.0 g / L. preferable.

  In order to control the ammonium ion concentration in the particle growth reaction aqueous solution within the above-described range, for example, an aqueous ammonia solution can be added to the particle growth reaction aqueous solution as necessary as described above.

  Although the temperature of the particle growth reaction aqueous solution is not particularly limited, it is preferably maintained at 20 ° C. or more and 60 ° C. or less, and more preferably 30 ° C. or more and 50 ° C. or less during the particle growth process. This is preferable by setting the temperature of the particle growth reaction aqueous solution to 20 ° C. or more and 60 ° C. or less so that the energy for heating the particle growth reaction aqueous solution can be suppressed to the minimum while the particle growth reaction sufficiently proceeds. Because.

  As explained so far, it is preferable to maintain the temperature of the reaction aqueous solution at 20 ° C. or higher and 60 ° C. or lower during the nucleation step and the particle growth step, that is, during the crystallization step. More preferably, the following is maintained.

  As the mixed aqueous solution, alkaline aqueous solution, and aqueous ammonia solution used in the particle growth step, the same materials as those already described in the nucleation step can be used. For this reason, explanation is omitted here.

  As for the mixed aqueous solution, as already described in the nucleation step, the compound containing each metal of nickel, cobalt, manganese, and optional additional elements does not necessarily have to be a mixed aqueous solution. For example, by mixing a plurality of metal compounds, when specific metal compounds react with each other to generate an unnecessary compound, an aqueous solution containing the metal compounds can be individually prepared. And you may add simultaneously the aqueous solution containing each prepared metal compound to the nucleation reaction aqueous solution after pH adjustment, and particle growth reaction aqueous solution in a predetermined ratio.

  As described above in the nucleation step, the total concentration of the above-described metal compounds in the mixed aqueous solution is preferably 1.0 mol / L or more and 2.6 mol / L or less, and 1.5 mol / L or more and 2. More preferably, it is 2 mol / L or less. And when adding the aqueous solution containing the metal compound added individually as described above to the particle growth reaction aqueous solution or the like, the concentration of the total metal compound in the aqueous solution containing the individually added metal compound is within the above range. It is preferable to adjust and add so that it may become.

  Further, in the nucleation step and the particle growth step, the mixed aqueous solution, the alkaline aqueous solution, and the aqueous ammonia solution can be used in the same concentration and solute, respectively. Among the mixed aqueous solution, the alkaline aqueous solution, and the aqueous ammonia solution, Some or all aqueous solutions may have different concentrations and / or solutes. However, in the method for producing nickel-cobalt-manganese composite hydroxide particles of the present embodiment, the composition ratio of each metal of nickel, cobalt, manganese, and additive elements in the obtained nickel-cobalt-manganese composite hydroxide particles is the same in the mixed aqueous solution. It becomes the same as the composition ratio of each metal. For this reason, it is preferable that the composition ratio of each metal in the mixed aqueous solution used in the particle growth step is the same as that in the nucleation step.

  As described above, in the method for producing nickel cobalt manganese composite hydroxide particles of the present embodiment, the crystallization step is preferably performed in an oxygen-containing gas atmosphere. Therefore, an oxygen-containing gas, for example, air can be blown into the reaction tank also in the particle growth step. By carrying out the particle growth step in an oxygen-containing gas atmosphere in this way, the product can sufficiently react with dissolved oxygen contained in the particle growth reaction aqueous solution, oxygen contained in the supplied oxygen-containing gas, and the like. Thus, an oxide needle plate-like crystal can be produced. And the obtained needle-plate-like crystal | crystallization can further aggregate and can produce | generate a big secondary particle. For this reason, the secondary particles of the obtained nickel cobalt manganese composite hydroxide particles can have a structure in which primary particles composed of needle plate crystals are aggregated.

  Since the process from the nucleation process to the particle growth process can be carried out continuously in the reaction tank, an oxygen-containing gas such as air is continuously introduced into the reaction tank after the start of the nucleation process. Can be supplied.

  Since dissolved oxygen in the particle growth reaction aqueous solution is consumed during the particle growth reaction, whether the supply amount of the oxygen-containing gas is sufficient is the amount of dissolved oxygen in the particle growth reaction aqueous solution as in the nucleation step. It can be confirmed by measuring. If the amount of dissolved oxygen in the particle growth reaction aqueous solution is more than half of the saturation amount, sufficient dissolved oxygen is present in the reaction, and oxygen can be sufficiently supplied. On the other hand, if the amount of dissolved oxygen in the aqueous solution for particle growth is less than half of the saturation amount, the amount of dissolved oxygen in the aqueous solution for particle growth reaction may not be sufficient. It is preferable.

  The pH value, ammonium ion concentration, and dissolved oxygen amount in the particle growth reaction aqueous solution can be measured by a general pH meter, ion meter, and dissolved oxygen meter, respectively.

  The particle size of the nickel cobalt manganese composite hydroxide particles can be controlled mainly by the reaction time of the particle growth step. For this reason, in the particle growth step, nickel cobalt manganese composite hydroxide particles having a desired particle diameter can be obtained if the reaction is continued until it grows to a desired particle diameter.

  Although the structure of the reaction vessel used in the crystallization step of the method for producing nickel cobalt manganese composite hydroxide particles of the present embodiment is not particularly limited, the product is nickel cobalt manganese composite hydroxide particles until the crystallization step is completed. It is preferable to use an apparatus that does not recover the amount. Examples of such an apparatus include a normally used batch reaction tank equipped with a stirrer.

  By using a reaction tank that does not collect the product until the crystallization process such as a batch reaction tank is completed, the growing particles overflow like a continuous crystallizer that collects the product by general overflow. The problem of being collected at the same time as the liquid can be prevented. For this reason, particles having a narrow particle size distribution and a uniform particle size can be obtained.

  As described so far, the crystallization step is preferably performed in an oxygen-containing gas atmosphere, and the atmosphere in the reaction vessel is preferably controlled. For this reason, it is preferable to use an apparatus capable of controlling the atmosphere, such as a sealed apparatus.

  By using a reaction vessel capable of controlling the atmosphere in this way, and making the inside of the reaction vessel an oxygen-containing gas atmosphere, for example, an air atmosphere, the nickel cobalt manganese composite hydroxide particles have the structure described above. And the coprecipitation reaction can proceed almost uniformly. For this reason, particles having an excellent particle size distribution, that is, particles having a narrow particle size distribution range can be obtained.

In addition to the crystallization process described above, the method for producing nickel cobalt manganese composite hydroxide particles of the present embodiment can have an optional process. Hereinafter, a configuration example of an arbitrary process will be described.
(Coating process)
The method for producing nickel cobalt manganese composite hydroxide particles of the present embodiment can also include a coating step of coating the nickel cobalt manganese composite hydroxide particles obtained in the crystallization step with an additive element.

  Here, the additive element means one or more additive elements selected from the above-described Mg, Ca, Al, Ti, V, Cr, Zr, Nb, Mo, and W.

  In the coating step, the specific method and conditions for coating the surface of the nickel cobalt manganese composite hydroxide particles with the additive element are not particularly limited. In the coating step, for example, any of the following methods can be used as a method of coating the nickel cobalt manganese composite hydroxide particles with the additive element.

A method in which an aqueous solution containing an additive element is added to a liquid in which nickel-cobalt-manganese composite hydroxide particles whose pH has been controlled are suspended, and the additive element is precipitated on the surface of the nickel-cobalt-manganese composite hydroxide particles (precipitation method) ).
In addition, when implementing a coating process by the above-mentioned precipitation method, when adding the aqueous solution containing an additional element to the slurry in which nickel cobalt manganese composite hydroxide particles were suspended, mixing the slurry and the aqueous solution containing the additional element It is preferable to control the pH of the slurry so that the pH of the aqueous solution is 5.5 or more and 8.0 or less.

  A method of spray drying a slurry in which nickel cobalt manganese composite hydroxide particles and a compound containing an additive element are suspended (spray drying method).

  A method in which nickel cobalt manganese composite hydroxide particles and a compound containing an additive element are mixed by a solid phase method (solid phase method).

  The aqueous solution containing the additive element used in the above-described precipitation method is not particularly limited. For example, an aqueous solution in which the compound containing the additive element described in the nucleation step is dissolved in water can be used. In the coating step, an alkoxide solution containing the additive element can be used instead of the aqueous solution containing the additive element.

  The compound containing the additive element used in the spray drying method or the solid phase method is not particularly limited, and for example, the compound containing the additive element described in the nucleation step can be used.

  As described above, in the nucleation step or particle growth step, a compound containing an additive element is added to the mixed aqueous solution, and the surface of the nickel cobalt manganese composite hydroxide particles is coated with the additive element in the coating step It is preferable that the amount of the compound containing the additive element added to the mixed aqueous solution in the nucleation step and the particle growth step is reduced by the amount to be coated in the coating step. This is because the addition amount of the compound containing the additive element to the mixed aqueous solution is reduced by the amount to be coated in the coating step, and the additive element contained in the obtained nickel cobalt manganese composite hydroxide particles and This is because the atomic ratio with other metal components can be set to a desired value.

The coating step can also be performed after the particle growth step is completed, for example, after a drying step described later is performed.
(Washing process)
The manufacturing method of the nickel cobalt manganese composite hydroxide particle of this embodiment can also have the washing | cleaning process of wash | cleaning the obtained nickel cobalt manganese composite hydroxide particle.

  In the washing step, for example, the slurry containing nickel cobalt manganese composite hydroxide particles obtained in the crystallization step and the coating step described above is washed.

  When performing a washing | cleaning process, the slurry containing nickel cobalt manganese composite hydroxide particle can be first filtered (filtration step).

  Next, the filtered nickel cobalt manganese composite hydroxide particles can be washed with water and filtered again (water washing / refiltration step).

  The filtration in the filtration step and the water washing / refiltration step may be performed by a commonly used method. For example, the filtration can be performed using a centrifuge, a suction filter, or the like.

Moreover, the water washing in the water washing / refiltration step may be carried out by a usual method as long as it can remove excess salt contained in the nickel cobalt manganese composite hydroxide particles. The water used in the water washing is preferably water having as little impurity content as possible, and more preferably pure water, in order to prevent contamination of impurities.
(Drying process)
The manufacturing method of the nickel cobalt manganese composite hydroxide particle of this embodiment can have a drying process.

  In the drying step, specifically, for example, the nickel cobalt manganese composite hydroxide particles washed in the washing step can be dried.

  In the drying step, the conditions for drying the nickel cobalt manganese composite hydroxide particles are not particularly limited. For example, the drying temperature is set to 100 ° C. or more and 200 ° C. or less, and the washed nickel cobalt manganese composite hydroxide particles are dried. Nickel cobalt manganese composite hydroxide particles can be obtained.

  According to the method for producing nickel cobalt manganese composite hydroxide particles of the present embodiment described above, primary particles composed of needle plate crystals are obtained by performing a crystallization reaction in an oxygen-containing gas atmosphere. Nickel cobalt manganese composite hydroxide particles having secondary particles having an aggregated structure can be obtained.

Further, in the method for producing nickel cobalt manganese composite hydroxide particles according to the present embodiment, the time mainly when the nucleation reaction occurs (nucleation process) and the time when the particle growth reaction mainly occurs (particle growth process) are clearly separated. can do. Therefore, even if both steps are performed in the same reaction vessel, nickel cobalt manganese composite hydroxide particles having a narrow particle size distribution can be obtained, and the positive electrode active material obtained from the nickel cobalt manganese composite hydroxide particles Can also have a narrow particle size distribution. As a result, deterioration of the positive electrode material can be suppressed and cycle characteristics can be improved.
[Lithium metal composite oxide particles]
Next, a configuration example of the lithium metal composite oxide particles of the present embodiment will be described.

In the present embodiment, the lithium metal composite oxide particles have a general formula: Li _{1 + α} Ni _x Co _y Mn _z M _t O ₂ (0.25 ≦ α ≦ 0.55, x + y + z + t = 1, 0.05 ≦ x ≦ 0.3, 0.1 ≦ y ≦ 0.4, 0.6 ≦ z ≦ 0.8, 0 ≦ t ≦ 0.1, M is an additive element, Mg, Ca, Al, Ti, V, Cr , One or more elements selected from Zr, Nb, Mo, and W).

  And it is preferable that the secondary particle of the lithium metal composite oxide particle of this embodiment is a porous particle, and the porosity inside the secondary particle is 10% or more and 30% or less.

The lithium metal composite oxide particles of the present embodiment are lithium-excess nickel cobalt manganese composite oxide particles in which two kinds of layered compounds represented by Li ₂ M1O ₃ and LiM2O ₂ are solid-solved. At this time, M1 is a metal element containing at least Mn adjusted to be tetravalent on average, M2 is a metal element containing at least Ni, Co, and Mn adjusted to be trivalent on average, and oxidized It is assumed that the composition ratio of Ni, Co, and Mn shown in the material precursor is M1 + M2. Moreover, since the abundance ratio of Li ₂ M1O ₃ and LiM2O ₂ is excess of lithium, Li ₂ M1O ₃ is not 0%.

  The lithium metal composite oxide particles of the present embodiment preferably have uniform pores up to the center of the secondary particles. With such a porous structure, when the lithium metal composite oxide particles are used as a positive electrode active material of a non-aqueous electrolyte secondary battery such as a lithium ion secondary battery, the reaction surface area with the electrolyte is reduced. Can be bigger. Further, the electrolyte enters from the grain boundaries or pores between the primary particles of the outer shell portion of the lithium metal composite oxide particles, and lithium is inserted and extracted at the reaction interface inside the particles. For this reason, the movement of Li ions and electrons is not hindered, and the output characteristics can be improved.

  And it is preferable that the porosity of the lithium metal complex oxide particle of this embodiment is 10% or more and 30% or less as mentioned above. This is because the reaction surface area with the electrolytic solution can be sufficiently increased by setting the porosity to 10% or more. However, when the porosity is too high, the tap density is lowered. Moreover, since it becomes easy to destroy a particle | grain, it is preferable that it is 30% or less. In addition, the porosity means the area ratio of the space | gap in the arbitrary cross sections of lithium metal complex oxide particle.

The lithium metal composite oxide particles of the present embodiment preferably have a specific surface area of 3.0 m ² / g or more, more preferably 5.0 m ² / g or more. In addition, although the upper limit of a specific surface area is not specifically limited, For example, it can be set as 12.0 m < ² > / g or less.

This is because when the specific surface area of the lithium metal composite oxide particles is 3.0 m ² / g or more, when the lithium metal composite oxide particles are used as the positive electrode active material of the non-aqueous electrolyte secondary battery, the electrolyte solution The reaction surface area can be particularly increased. For this reason, it is because reaction resistance can be suppressed and it can be set as a high output battery.

  The lithium metal composite oxide particles of this embodiment preferably have a tap density of 1.6 g / cc or more, and more preferably 1.8 g / cc or more. In addition, although the upper limit of tap density is not specifically limited, For example, it is preferable that it is 3.0 g / cc or less.

  This is because when the tap density of the lithium metal composite oxide particles is 1.6 cc / g or more and the lithium metal composite oxide particles are used as the positive electrode active material of the non-aqueous electrolyte secondary battery, the energy is particularly high. It is because it can be set as a battery of a density.

  As will be described later, the lithium metal composite oxide particles of the present embodiment can be produced using, for example, the nickel cobalt manganese composite hydroxide particles described above. For this reason, the specific surface area and the tap density can be adjusted, for example, by selecting the conditions in the crystallization process, that is, the time of the particle growth process, for example.

Furthermore, the discharge capacity under the high discharge rate condition (2C) of the non-aqueous electrolyte secondary battery using the lithium metal composite oxide particles of the present embodiment as the positive electrode active material is preferably 200 mAh / g or more, More preferably, it is 250 mAh / g or more.
[Method for producing lithium metal composite oxide particles]
Next, a configuration example of the method for producing the lithium metal composite oxide particles of the present embodiment will be described.

  The method for producing lithium metal composite oxide particles of the present embodiment is not particularly limited as long as the method can produce lithium metal composite oxide particles so that the lithium metal composite oxide particles have the particle structure described above. Absent. The method for producing lithium metal composite oxide particles of the present embodiment can include, for example, the following steps.

  A roasting process in which nickel cobalt manganese composite hydroxide particles are heat treated.

  A mixing step in which heat-treated nickel cobalt manganese composite hydroxide particles and a lithium compound are mixed to form a mixture.

  A firing step of firing the mixture formed in the mixing step.

Hereinafter, each step will be described.
(Roasting process)
In the roasting step, the nickel cobalt manganese composite hydroxide particles can be heat-treated, for example, water in the nickel cobalt manganese composite hydroxide particles is removed, and at least a part of the nickel cobalt manganese composite hydroxide particles is removed. It can be an oxide.

  The nickel cobalt manganese composite hydroxide particles described above can be used as the nickel cobalt manganese composite hydroxide particles.

  Although the heat treatment temperature in the roasting process is not particularly limited, the moisture contained in the nickel cobalt manganese composite hydroxide particles is removed by the heat treatment, and lithium and other metals in the lithium metal composite oxide particles finally obtained are removed. It is preferable to select such that the ratio of the number of atoms can be prevented from varying.

  In the roasting step, for example, the heat treatment is preferably performed at a temperature that is higher than the drying temperature in the drying step of the method for producing nickel cobalt manganese composite hydroxide particles described above and is 600 ° C. or lower. In particular, the heat treatment temperature is preferably 105 ° C. or higher and 600 ° C. or lower.

  If the heat treatment temperature in the roasting step is less than 105 ° C., excess water in the nickel cobalt manganese composite hydroxide particles cannot be removed, lithium in the lithium metal composite oxide particles finally obtained, This is because the variation in the ratio of the number of atoms of other metals may increase.

  Further, if the heat treatment temperature exceeds 600 ° C., the particles are sintered by roasting, and lithium metal composite oxide particles having a uniform particle size may not be obtained.

  In the roasting process, it is sufficient that water can be removed to such an extent that the ratio of the number of atoms of metals such as lithium in the finally obtained lithium metal composite oxide particles does not vary. There is no need to convert the hydroxide particles to nickel cobalt manganese composite oxide particles. However, in order to reduce the variation in the number of metal atoms in the obtained lithium metal composite oxide particles, the heat treatment temperature is set to 500 ° C. or more, and the nickel cobalt manganese composite hydroxide particles are changed to nickel cobalt manganese composite oxide particles. It is preferable to convert all of the above.

  For this reason, it is more preferable that the heat treatment temperature in the roasting step is, for example, 500 ° C. or more and 600 ° C. or less.

  In addition, the metal component contained in the nickel cobalt manganese composite hydroxide particles after the heat treatment at the predetermined heat treatment temperature in the roasting step is obtained in advance by analysis, and the nickel cobalt manganese composite after the heat treatment in the mixing step described later. It is preferable to determine the mixing ratio between the hydroxide particles and the lithium compound. Thus, by analyzing the ratio of each metal in the nickel cobalt manganese composite hydroxide particles after heat treatment obtained at a predetermined heat treatment temperature, and determining the optimal mixing ratio with the lithium compound, it is finally obtained. The variation in the ratio of the number of atoms of lithium and other metals in the obtained lithium metal composite oxide particles can be suppressed, which is preferable.

  The atmosphere during the heat treatment in the roasting step is not particularly limited and may be a non-reducing atmosphere, but is preferably performed in an air stream that can be easily performed.

  Further, the heat treatment time (roasting time) in the roasting step is not particularly limited, but if it is less than 1 hour, the excess moisture of the nickel cobalt manganese composite hydroxide particles may not be sufficiently removed, so that it is 1 hour or more. 2 hours or more are more preferable. The upper limit of the heat treatment time is not particularly limited, but is preferably 15 hours or less in consideration of productivity and the like.

The equipment used for roasting is not particularly limited as long as the nickel cobalt manganese composite hydroxide particles can be heated in a non-reducing atmosphere, preferably in an air stream, and gas generation is possible. A non-electric furnace or the like is preferably used.
(Mixing process)
In the mixing step, the nickel cobalt manganese composite hydroxide particles after heat treatment obtained in the roasting step (hereinafter referred to as “roasted particles”) and a lithium compound are mixed to obtain a mixture (mixed powder). It is a process.

  The roasted particles and the lithium compound are the ratio of the number of atoms of metals other than lithium in the mixture, that is, the sum of the number of atoms of nickel, cobalt, manganese and additive elements (Me) to the number of atoms of lithium (Li) ( It is preferable to mix so that Li / Me) may be 1.25 or more and 1.55 or less. In particular, it is more preferable to mix so that the ratio (Li / Me) of the number of lithium atoms in the mixture to the number of metal atoms other than lithium is 1.3 or more and 1.5 or less. Since Li / Me does not change before and after the firing step described later, Li / Me in the mixture used for the firing step is the same as Li / Me in the obtained lithium metal composite oxide particles. For this reason, it is preferable to mix so that Li / Me in the mixture prepared at a mixing process may become the same as Li / Me in the lithium metal complex oxide particle to be obtained.

  The lithium compound used to form the mixture is not particularly limited. For example, lithium hydroxide, lithium nitrate, lithium carbonate, or a mixture of two or more substances selected from these is available. Is preferable in that it is easy. In particular, in view of ease of handling and quality stability, it is more preferable to use at least one selected from lithium hydroxide and lithium carbonate as the lithium compound.

In the mixing step, a general mixer can be used as a mixing means when mixing the roasted particles and the lithium compound, and for example, a shaker mixer, a Laedige mixer, a Julia mixer, a V blender, or the like may be used. .
(Baking process)
The firing step is a step of firing the mixture obtained in the above mixing step to obtain lithium metal composite oxide particles. When the mixture is fired in the firing step, lithium in the lithium compound diffuses into the roasted particles, so that lithium metal composite oxide particles, more specifically lithium nickel cobalt manganese composite oxide particles are formed.

  In the firing step, the firing temperature for firing the mixture is not particularly limited, but is preferably 600 ° C. or more and 950 ° C. or less, and more preferably 700 ° C. or more and 900 ° C. or less.

  By setting the firing temperature to 600 ° C. or higher, the diffusion of lithium into the roasted particles can be sufficiently advanced, the crystal structure of the resulting lithium metal composite oxide can be made uniform, and the product This is because when used as a positive electrode active material, battery characteristics can be particularly improved. Further, since the reaction can be sufficiently advanced, it is possible to suppress surplus lithium and unreacted particles from remaining.

  By setting the firing temperature to 950 ° C. or lower, it is possible to suppress the progress of sintering between the generated lithium metal composite oxide particles. Moreover, generation | occurrence | production of abnormal grain growth can be suppressed and it can suppress that the lithium metal complex oxide particle obtained becomes coarse. Furthermore, fine pores can be reliably formed inside the particles. Therefore, the obtained lithium metal composite oxide particles can increase the specific surface area, and when used as a positive electrode material for a non-aqueous electrolyte secondary battery, the resistance of the positive electrode is suppressed and a high output battery is obtained. be able to.

  The rate of temperature rise up to the heat treatment temperature in the firing step is not particularly limited, but from the viewpoint of uniformly performing the reaction between the roasted particles and the lithium compound, the temperature rise rate is 3 ° C./min to 10 ° C./min. It is preferable to raise the temperature up to.

  Further, in the process of raising the temperature to the heat treatment temperature, it is preferable that the reaction can be performed more uniformly by maintaining the temperature in the vicinity of the melting point of the lithium compound used for about 1 hour to 5 hours.

  Of the firing time in the firing step, the holding time at the predetermined temperature, that is, the above-described firing temperature is not particularly limited, but is preferably 1 hour or longer, more preferably 2 hours or longer. This is because, by setting the holding time at the firing temperature to 2 hours or more, it is possible to sufficiently promote the formation of the lithium metal composite oxide and more reliably prevent the unreacted product from remaining.

  The upper limit of the holding time at the firing temperature is not particularly limited, but is preferably 24 hours or less in consideration of productivity and the like.

  The conditions after the end of the holding time at the firing temperature are not particularly limited. However, when the mixture is loaded on the mortar and baked, the descent rate is 2 ° C./min or more in order to suppress deterioration of the mortar. The atmosphere is preferably cooled to 10 ° C./min or less until it becomes 200 ° C. or less.

  The atmosphere during firing is not particularly limited, but an oxidizing atmosphere is preferable. As the oxidizing atmosphere, an oxygen-containing gas atmosphere can be preferably used. For example, an atmosphere having an oxygen concentration of 18% by volume to 100% by volume is more preferable.

  This is because the crystallinity of the lithium metal composite oxide can be particularly enhanced by setting the oxygen concentration in the atmosphere during firing to 18% by volume or more.

  In the case of an oxygen-containing gas atmosphere, as a gas constituting the atmosphere, for example, air, oxygen, a mixed gas of oxygen and an inert gas, or the like can be used.

  In addition, as a gas which comprises oxygen-containing gas atmosphere, when using the mixed gas of oxygen and an inert gas as mentioned above, it is preferable that the oxygen concentration in this mixed gas satisfy | fills the above-mentioned range.

  In particular, the firing step is preferably performed in an oxygen-containing gas stream, and more preferably in the air or an oxygen stream. Considering battery characteristics in particular, it is preferably performed in an oxygen stream.

  The furnace used for firing is not particularly limited as long as the mixture can be fired in a predetermined atmosphere. From the viewpoint of maintaining a uniform atmosphere in the furnace, an electric furnace that does not generate gas. It is preferable to use either a batch type or continuous type furnace.

  The lithium metal composite oxide particles obtained by the firing step may be aggregated or slightly sintered. In this case, it may be crushed, whereby lithium metal composite oxide particles can be obtained.

  Here, pulverization refers to almost destroying the secondary particles themselves by applying mechanical energy to an aggregate composed of a plurality of secondary particles generated by sintering necking between secondary particles during firing. It is an operation of separating the secondary particles and loosening the aggregates.

  In addition, when lithium hydroxide or lithium carbonate is used as the lithium compound, it is preferable to perform temporary firing before the firing step.

  When carrying out the pre-baking, the pre-baking temperature is not particularly limited, but can be set to a temperature lower than the baking temperature in the baking step. The pre-baking temperature is preferably 250 ° C. or higher and 600 ° C. or lower, and more preferably 350 ° C. or higher and 550 ° C. or lower.

  The calcination time, that is, the holding time at the calcination temperature is preferably about 1 hour to 10 hours, and more preferably 3 hours to 6 hours.

  After temporary calcination, it can be cooled and then subjected to a calcination step, but the calcination step can also be carried out continuously by raising the temperature from the calcination temperature to the calcination temperature.

  In addition, although the atmosphere at the time of implementing temporary baking is not specifically limited, For example, it can be set as the atmosphere similar to a baking process.

By calcination, lithium is sufficiently diffused into the roasted particles, and particularly uniform lithium metal composite oxide particles can be obtained.
[Non-aqueous electrolyte secondary battery]
Next, a configuration example of the non-aqueous electrolyte secondary battery of this embodiment will be described.

  The non-aqueous electrolyte secondary battery of this embodiment can have a positive electrode using the above-described lithium metal composite oxide particles as a positive electrode material.

  First, the structural example of the structure of the non-aqueous electrolyte secondary battery of this embodiment is demonstrated.

  The non-aqueous electrolyte secondary battery of this embodiment has substantially the same structure as a general non-aqueous electrolyte secondary battery except that the lithium metal composite oxide particles described above are used as the positive electrode material. Can be provided.

  Specifically, the non-aqueous electrolyte secondary battery of this embodiment can have a structure including a case and a positive electrode, a negative electrode, a non-aqueous electrolyte, and a separator housed in the case.

  More specifically, a positive electrode and a negative electrode can be laminated through a separator to form an electrode body, and the obtained electrode body can be impregnated with a nonaqueous electrolytic solution. Then, between the positive electrode current collector of the positive electrode and the positive electrode terminal that communicates with the outside, and between the negative electrode current collector of the negative electrode and the negative electrode terminal that communicates with the outside using a current collecting lead, etc., respectively, It can have a sealed structure.

  It should be noted that the structure of the non-aqueous electrolyte secondary battery of the present embodiment is not limited to the above example, and various shapes such as a cylindrical shape and a stacked shape can be adopted as the outer shape.

A configuration example of each member will be described below.
(Positive electrode)
First, the positive electrode will be described.

  The positive electrode is a sheet-like member, and the above-described lithium metal composite oxide particles can be used as the positive electrode active material.

  For example, the positive electrode can be formed by applying and drying the positive electrode mixture paste containing the lithium metal composite oxide particles described above on the surface of a current collector made of, for example, an aluminum foil. In addition, a positive electrode is suitably processed according to the battery to be used. For example, a cutting process for forming an appropriate size according to a target battery, a pressure compression process using a roll press or the like for increasing the electrode density, and the like can be performed.

  The above-mentioned positive electrode mixture paste can be formed by adding a solvent to the positive electrode mixture and kneading. The positive electrode mixture can be formed by mixing the above-described lithium metal composite oxide particles in a powder form, a conductive material, and a binder.

  The conductive material is added to give an appropriate conductivity to the electrode. The material of the conductive material is not particularly limited. For example, graphite such as natural graphite, artificial graphite and expanded graphite, and carbon black materials such as acetylene black and ketjen black can be used.

  The binder plays a role of tethering lithium metal composite oxide particles that are positive electrode active materials. The binder used for such a positive electrode mixture is not particularly limited. For example, polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), fluororubber, ethylene propylene diene rubber, styrene butadiene, cellulose resin, polyacrylic. One or more selected from acids and the like can be used.

  In addition, activated carbon etc. can also be added to a positive electrode compound material. By adding activated carbon or the like to the positive electrode mixture, the electric double layer capacity of the positive electrode can be increased.

  The solvent has a function of dissolving the binder and dispersing the positive electrode active material, the conductive material, activated carbon, and the like in the binder. Although the solvent is not particularly limited, for example, an organic solvent such as N-methyl-2-pyrrolidone can be used.

Moreover, the mixing ratio of each substance in the positive electrode mixture paste is not particularly limited, and can be the same as that of the positive electrode of a general non-aqueous electrolyte secondary battery, for example. For example, when the solid content of the positive electrode mixture excluding the solvent is 100 parts by mass, the content of the positive electrode active material is 60 parts by mass or more and 95 parts by mass or less, and the content of the conductive material is 1 part by mass or more and 20 parts by mass or less. The binder content can be 1 part by mass or more and 20 parts by mass or less.
(Negative electrode)
The negative electrode is a sheet-like member formed by applying a negative electrode mixture paste to the surface of a metal foil current collector such as copper and drying it.

  The negative electrode is formed by substantially the same method as the positive electrode described above, although the components constituting the negative electrode mixture paste, the composition thereof, and the current collector material are different. Done.

  The negative electrode mixture paste can be made into a paste by adding an appropriate solvent to the negative electrode mixture obtained by mixing the negative electrode active material and the binder.

  As the negative electrode active material, for example, a material containing lithium, such as metallic lithium or a lithium alloy, or an occlusion material that can occlude and desorb lithium ions can be employed.

  The occlusion material is not particularly limited, and for example, one or more selected from natural graphite, artificial graphite, a fired organic compound such as phenol resin, and a powdery carbon material such as coke can be used.

When such an occlusion material is employed as the negative electrode active material, a fluorine-containing resin such as PVDF can be used as the binder, as with the positive electrode, and as a solvent for dispersing the negative electrode active material in the binder, An organic solvent such as N-methyl-2-pyrrolidone can be used.
(Separator)
The separator is disposed between the positive electrode and the negative electrode, and has a function of separating the positive electrode and the negative electrode and holding the electrolytic solution.

As a material for the separator, for example, a thin film such as polyethylene or polypropylene and a film having a large number of fine holes can be used. However, the separator is not particularly limited as long as it has the above function.
(Non-aqueous electrolyte)
The nonaqueous electrolytic solution is obtained by dissolving a lithium salt as a supporting salt in an organic solvent.

  Examples of the organic solvent include cyclic carbonates such as ethylene carbonate, propylene carbonate, butylene carbonate, and trifluoropropylene carbonate; chain carbonates such as diethyl carbonate, dimethyl carbonate, ethyl methyl carbonate, and dipropyl carbonate; Ether compounds such as methyltetrahydrofuran and dimethoxyethane; sulfur compounds such as ethyl methyl sulfone and butane sultone; phosphorus compounds such as triethyl phosphate and trioctyl phosphate alone or in combination of two or more. be able to.

As the supporting salt, LiPF ₆ , LiBF ₄ , LiClO ₄ , LiAsF ₆ , LiN (CF ₃ SO ₂ ) ₂ , and complex salts thereof can be used.

  In addition, the non-aqueous electrolyte solution may contain a radical scavenger, a surfactant, a flame retardant, and the like for improving battery characteristics.

  In the above, the structural example of each member of the non-aqueous electrolyte secondary battery has been described.

  Since the non-aqueous electrolyte secondary battery of the present embodiment has a positive electrode using the above-described lithium metal composite oxide particles as a positive electrode active material, a low positive electrode resistance is obtained and a high output battery is obtained. be able to.

  For this reason, the non-aqueous electrolyte secondary battery of this embodiment can be suitably used as a battery for a motor driving power source that requires a high output.

  The lithium metal composite oxide particles described above can also have a high tap density, and the non-aqueous electrolyte secondary battery of this embodiment using the lithium metal oxide as a positive electrode active material has a high capacity. It can be. For this reason, the non-aqueous electrolyte secondary battery of the present embodiment is preferably used for a power source of a small portable electronic device that always requires a high capacity, specifically, for example, a notebook personal computer or a mobile phone terminal. it can.

  Moreover, since the non-aqueous battery of this embodiment can achieve high capacity as described above, the volume per capacity can be reduced. That is, the size can be reduced.

  As batteries become larger, it becomes difficult to ensure safety and an expensive protection circuit is indispensable.However, the nonaqueous electrolyte secondary battery of this embodiment can be downsized, and therefore has excellent safety. Therefore, it is possible not only to ensure safety, but also to simplify an expensive protection circuit and reduce the cost.

  And since the non-aqueous electrolyte secondary battery of this embodiment can be reduced in size and increased in output as described above, it can be suitably used as a power source for transportation equipment that is restricted by the mounting space. .

  Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to the following examples.

  The sample preparation conditions and evaluation results in each example and comparative example are described below.

Throughout all the examples, nickel-cobalt-manganese composite hydroxide particles, lithium metal composite oxide particles, and non-aqueous electrolyte secondary batteries were prepared using Wako Pure Chemical Industries, Ltd. reagent special grade samples. used.
[Example 1]
(1) Production of Nickel Cobalt Manganese Composite Hydroxide Particles Nickel cobalt manganese composite hydroxide particles were produced as follows according to the flow shown in FIG.
(Adjustment of mixed aqueous solution)
Nickel sulfate, cobalt sulfate, and manganese sulfate were dissolved in water to prepare a 2.0 mol / L mixed aqueous solution. Each metal compound was added to water and mixed so that the element molar ratio of each metal in this mixed aqueous solution was Ni: Co: Mn = 0.165: 0.165: 0.67.
(Crystallization process)
Next, as a crystallization process, the following nucleation process and particle growth process were performed.
(Nucleation process)
First, the temperature in the tank was set to 40 ° C. while stirring by putting water in an amount of about 1.2 L in a reaction tank having a capacity of 5 L. And the liquid temperature of initial stage aqueous solution and reaction aqueous solution was maintained at 40 degreeC until the crystallization process was completed. The reaction aqueous solution refers to a nucleation reaction aqueous solution, a pH-adjusted nucleation reaction aqueous solution, and a particle growth reaction aqueous solution.

  Next, an appropriate amount of 25% by mass ammonia water was added to the water in the reaction vessel so that the ammonium ion concentration of the initial aqueous solution was 5 g / L.

  Furthermore, 25 mass% sodium hydroxide aqueous solution was added to the water in a reaction tank as alkaline aqueous solution, pH was adjusted to 11.0, and it was set as initial stage aqueous solution.

  And the inside of the reaction tank was purged by supplying air into the reaction tank at 4 L / min from the air compressor, and the inside of the reaction tank was made into an oxygen-containing gas atmosphere, specifically an air atmosphere. Note that air was continuously supplied during the crystallization process.

  After purging the inside of the reaction tank with air, the above-mentioned mixed aqueous solution was added to the initial aqueous solution in the reaction tank at an addition rate of 10.3 ml / min for 4 minutes (this time is referred to as “addition time” in Table 1). A nucleation reaction aqueous solution was prepared.

  In addition, when adding the mixed aqueous solution to the initial aqueous solution, the above-described alkaline aqueous solution and aqueous ammonia are added together so that the pH value of the aqueous solution of nucleation reaction is 11.0 based on the liquid temperature of 40 ° C. The ammonium ion concentration was controlled to 5 g / L. It was confirmed that the fluctuation range of the pH was within ± 0.1 of 11.0 which is the pH set value. Moreover, it was confirmed that the fluctuation range of the ammonium ion concentration was within ± 1.0 g / L of 5 g / L, which is the set ammonium ion concentration.

And after continuing reaction for 4 minutes by adding mixed aqueous solution as mentioned above, only stirring was continued for 5 minutes.
(Particle growth process)
After completion of the nucleation step, 64% sulfuric acid was added dropwise until the pH value of the aqueous nucleation reaction solution reached 10.5 based on the liquid temperature of 40 ° C., and the pH was adjusted.

  Next, the above-described mixed aqueous solution was added to the nucleation reaction aqueous solution after pH adjustment at an addition rate of 10.3 ml / min for 100 minutes to prepare a particle growth reaction aqueous solution.

  When the mixed aqueous solution is added to the pH-adjusted nucleation reaction aqueous solution, the same alkaline aqueous solution and ammonia water as in the nucleation step are added together, and the pH value of the particle growth reaction aqueous solution is 10.5 on a 40 ° C. basis. And the ammonium ion concentration was controlled to be 5 g / L. It was confirmed that the fluctuation range of the pH was within ± 0.1 of 10.5 which is the set pH value. Moreover, it was confirmed that the fluctuation range of the ammonium ion concentration was within ± 1.0 g / L of 5 g / L, which is the set ammonium ion concentration.

And by adding mixed aqueous solution as mentioned above, reaction was continued for 100 minutes and the particle growth process was complete | finished. During the addition of the mixed aqueous solution, stirring of the aqueous nucleation reaction solution or particle growth reaction aqueous solution after pH adjustment is continuously performed.
(Washing process)
The slurry containing nickel cobalt manganese composite hydroxide particles obtained in the crystallization step was filtered, washed with water, and filtered again.

Note that pure water was used for washing with water. Further, a suction filter was used as a filtering means during the filtration.
(Drying process)
The nickel cobalt manganese composite hydroxide particles separated and washed from the slurry in the washing step were dried at 120 ° C. in an air atmosphere.

  Nickel cobalt manganese composite hydroxide particles were obtained by the above process.

  The obtained nickel-cobalt-manganese composite hydroxide particles were dissolved in an inorganic acid and then subjected to chemical analysis by ICP emission spectroscopy. The composition was Ni: Co: Mn = 15.9 at%: 16.7 at%: It was confirmed that it was 67.4 at%.

  The obtained nickel-cobalt-manganese composite hydroxide particles were observed with a scanning electron microscope SEM (manufactured by Hitachi High-Technologies Corporation, scanning electron microscope S-4700, magnification 1000 times). It was confirmed that the primary particles composed of the crystals had an agglomerated structure. Further, it was confirmed that the secondary particles were substantially spherical and the particle diameter was almost uniform.

As for the obtained nickel cobalt manganese composite hydroxide particles, the average particle size D50 was measured using a laser diffraction / scattering particle size distribution analyzer (manufactured by Nikkiso Co., Ltd., Microtrac HRA). It was confirmed to be 4 μm.
(2) Production of lithium metal composite oxide particles Lithium metal composite oxide particles were produced by the following procedure.
(Roasting process)
The obtained nickel-cobalt-manganese composite hydroxide particles are heat-treated at 500 ° C. for 2 hours in air (oxygen: 21 vol%) airflow to remove the water contained in the nickel-cobalt composite hydroxide particles. It was removed and converted to nickel cobalt manganese composite oxide particles and recovered.
(Mixing process)
In the mixing step, heat-treated nickel cobalt manganese composite hydroxide particles, that is, nickel cobalt manganese composite oxide particles, and lithium carbonate, which is a lithium compound, were mixed to prepare a mixture.

  When mixing both components, the metal component in the heat-treated nickel-cobalt-manganese composite hydroxide particles, that is, the sum of the number of atoms of nickel, cobalt and manganese is Me, and the number of lithium atoms in lithium carbonate is Li. In this case, both components were weighed and mixed so that Li / Me = 1.5.

Mixing was performed using a shaker mixer apparatus (manufactured by Willy et Bacofen (WAB), TURBULA Type T2C).
(Baking process)
The mixture obtained in the mixing step was calcined at 500 ° C. for 5 hours in the atmosphere (oxygen: 21% by volume), and then calcined at 800 ° C. for 2 hours.

  After firing, the mixture was cooled to room temperature and then crushed to obtain lithium metal composite oxide particles.

  In addition, after calcination, after cooling once, calcination at 800 ° C. (main calcination) is performed, and the temperature rise rate at the time of calcination is 5 ° C./min and held at the calcination temperature for 2 hours. .

  With respect to the obtained lithium metal composite oxide particles, the particle size distribution was measured by the same method as that for the nickel cobalt manganese composite hydroxide particles described above. As a result, the average particle size was 6.4 μm.

  Further, when the obtained lithium metal composite oxide particles were subjected to cross-sectional SEM observation, the obtained lithium metal composite oxide particles had a porous structure having uniform pores up to the center inside the secondary particles. It was confirmed that

  As a result of observing 100 or more particles of the cross-sectional SEM image, it was confirmed that the ratio of the particles having pores to the center (porous particles) was 100%. The porosity of the secondary particles was measured using image analysis software and found to be 24%.

  The SEM uses the same apparatus as that used for evaluating nickel cobalt manganese composite hydroxide particles.

  Furthermore, when the tap density of the obtained lithium metal composite oxide particles was evaluated, it was confirmed to be 1.7 g / cc.

  The tap density was measured after the obtained lithium metal composite oxide particles were filled into a 20 ml graduated cylinder, and then the graduated cylinder was packed closely by a method in which free fall from a height of 2 cm was repeated 500 times.

Further, when the specific surface area of the obtained positive electrode active material was determined by a flow method gas adsorption method specific surface area measurement device (manufactured by Yuasa Ionics Co., Ltd., Multisorb), it was confirmed to be 10.4 m ² / g.
(3) Manufacture of non-aqueous electrolyte secondary battery Using the obtained lithium metal composite oxide particles as a positive electrode active material, a 2032 type coin battery was manufactured and evaluated.

  The configuration of the coin-type battery manufactured using FIG. 2 will be described. FIG. 2 is a schematic cross-sectional view of the manufactured coin battery.

  As shown in FIG. 2, the manufactured coin battery 10 includes a case 11 and an electrode 12 accommodated in the case 11.

  The case 11 has a positive electrode can 111 that is hollow and open at one end, and a negative electrode can 112 that is disposed in the opening of the positive electrode can 111, and the negative electrode can 112 is disposed in the opening of the positive electrode can 111. A space for accommodating the electrode 12 is formed between the negative electrode can 112 and the positive electrode can 111.

  The electrode 12 includes a positive electrode 121, a separator 122, and a negative electrode 123, which are stacked in this order, so that the positive electrode 121 is in contact with the inner surface of the positive electrode can 111 and the negative electrode 123 is in contact with the inner surface of the negative electrode can 112. In the case 11.

  The case 11 includes a gasket 113, and the gasket 113 is fixed so as to maintain an electrically insulated state between the positive electrode can 111 and the negative electrode can 112. In addition, the gasket 113 has a function of sealing the gap between the positive electrode can 111 and the negative electrode can 112 and blocking the inside and outside of the case 11 in an airtight and liquidtight manner.

  This coin-type battery 10 was produced as follows. First, 52.5 mg of the obtained lithium metal composite oxide particles, 15 mg of acetylene black, and 7.5 mg of polytetrafluoroethylene resin (PTFE) were mixed with N-methyl-2-pyrrolidone as a solvent, and at a pressure of 100 MPa. The positive electrode 121 was manufactured by press molding to a diameter of 11 mm and a thickness of 100 μm. The produced positive electrode 121 was dried in a vacuum dryer at 120 ° C. for 12 hours. Using the positive electrode 121, the negative electrode 123, the separator 122, and the electrolytic solution, the coin-type battery 10 was produced in a glove box in an Ar atmosphere in which the dew point was controlled at −80 ° C.

For the negative electrode 123, a negative electrode mixture paste prepared by mixing graphite powder punched into a disk shape with a diameter of 14 mm and an average particle diameter of about 20 μm and polyvinylidene fluoride together with N-methyl-2-pyrrolidone as a solvent is copper. A negative electrode sheet coated and dried on a foil was used. The separator 122 was a polyethylene porous film with a film thickness of 25 μm. As the electrolytic solution, an equivalent mixed solution of ethylene carbonate (EC) and diethyl carbonate (DEC) using 1M LiClO ₄ as a supporting electrolyte (manufactured by Toyama Pharmaceutical Co., Ltd.) was used.

  The initial discharge capacity for evaluating the performance of the obtained coin-type battery 10 was defined as follows.

  The initial discharge capacity is left for about 24 hours after the coin-type battery 10 is manufactured, and after the open circuit voltage OCV (open circuit voltage) is stabilized, the current density with respect to the positive electrode is 0.05 C (270 mA / g is 1 C). ) To a cut-off voltage of 4.65 V, the capacity when discharged to a cut-off voltage of 2.35 V after a pause of 1 hour was defined as the initial discharge capacity.

  When a coin-type battery having a positive electrode formed using the lithium metal composite oxide particles as a positive electrode active material was evaluated, the initial discharge capacity was 280 mAh / g. In addition, in order to evaluate the high discharge rate characteristics, the charge / discharge capacity was measured at 0.01 C, and then the charge / discharge capacity was measured three times at 0.2 C, 0.5 C, and 1.0 C, and then 3 at 2.0 C. The average value measured once was taken as the discharge capacity at a high discharge rate. The value was 211 mAh / g.

Table 1 summarizes the production conditions of this example, Table 2 shows the evaluation results of the composition of the nickel cobalt manganese composite hydroxide particles obtained in this example, the evaluation results of the lithium metal composite oxide particles, Table 3 shows the evaluation results of coin-type batteries manufactured using the lithium metal composite oxide particles as positive electrode active materials. The same contents are shown in the same table for Example 2 and Comparative Examples 1 and 2 below.
[Example 2]
The same as in Example 1 except that the addition time in the particle growth step during the production of nickel cobalt manganese composite hydroxide particles, that is, the addition time of the mixed aqueous solution to the aqueous solution of nucleation reaction after pH adjustment was changed to 196 minutes. Then, nickel cobalt manganese composite hydroxide particles, lithium metal composite oxide particles, and a non-aqueous electrolyte secondary battery were manufactured and evaluated.

  The evaluation results are shown in Tables 1 to 3.

The particle diameter is increased by increasing the time of the particle growth process. However, the battery characteristics were the same as in Example 1.
[Comparative Example 1]
In the crystallization step when producing nickel cobalt manganese composite hydroxide particles, the nickel gas containing the oxygen in the reaction vessel was changed to nitrogen gas containing no oxygen, in the same manner as in Example 2 except that Cobalt-manganese composite hydroxide particles, lithium metal composite oxide particles, and non-aqueous electrolyte secondary batteries were manufactured and evaluated.

  The evaluation results are shown in Tables 1 to 3.

As for the nickel cobalt manganese compound hydroxide particles of Examples 1 and 2, it was confirmed that the secondary particles had a structure in which primary particles composed of needle plate crystals were aggregated.

  Also, with respect to lithium metal composite oxide particles produced using each nickel cobalt manganese composite hydroxide particles, the secondary particles are porous particles having a porous structure having pores up to the center of the secondary particles. It was confirmed that the porosity inside the secondary particles was 10% or more and 30% or less.

  Furthermore, it was also confirmed that the nickel cobalt manganese composite hydroxide particles of Examples 1 and 2 and the lithium metal composite oxide particles were all particles having a substantially uniform particle size.

  Therefore, the coin-type battery using the lithium metal composite oxide particles of Examples 1 and 2 as the positive electrode active material can reduce the reaction resistance at the positive electrode, has a high initial discharge capacity, and a high discharge rate. The discharge capacity of the battery is high, and the battery is a non-aqueous electrolyte secondary battery with high output even during rapid charge / discharge.

  On the other hand, it was confirmed that the nickel cobalt manganese composite hydroxide particles of Comparative Example 1 had a secondary particle structure in which plate crystals were randomly entangled. Moreover, it was confirmed that the lithium metal composite oxide particles produced using the nickel cobalt manganese composite hydroxide particles were dense particles having no pores inside the secondary particles. .

  For this reason, the coin-type battery manufactured using the lithium metal composite oxide particles of Comparative Example 1 as the positive electrode active material has high reaction resistance at the positive electrode, and compared with Examples 1 and 2, the initial discharge capacity, and It was confirmed that the discharge capacity at a high discharge rate was inferior and the output was lowered.

  From the above results, when a non-aqueous electrolyte secondary battery is manufactured using lithium metal composite oxide particles that are porous particles and have a predetermined porosity, the reaction resistance at the positive electrode is suppressed and initial discharge is suppressed. The capacity and the discharge capacity at a high discharge rate can be increased, and it was confirmed that the non-aqueous electrolyte secondary battery has excellent output characteristics.

  In addition, it was also confirmed that the lithium metal composite oxide particles were obtained using nickel cobalt manganese composite hydroxide particles having a structure in which the primary particles composed of needle-plate-like crystals were aggregated. .

Claims (10)

General formula: Ni _x Co _y Mn _z M _t (OH) _{2 + a} (x + y + z + t = 1, 0.05 ≦ x ≦ 0.3, 0.1 ≦ y ≦ 0.4, 0.6 ≦ z ≦ 0.8, 0 ≦ t ≦ 0.1, 0 ≦ a ≦ 0.5, M is one or more additive elements selected from Mg, Ca, Al, Ti, V, Cr, Zr, Nb, Mo, and W) Nickel cobalt manganese composite hydroxide particles represented,
The secondary particles of the nickel cobalt manganese composite hydroxide particles are nickel cobalt manganese composite hydroxide particles having a structure in which primary particles composed of needle plate crystals are aggregated. General formula: Ni _x Co _y Mn _z M _t (OH) _{2 + a} (x + y + z + t = 1, 0.05 ≦ x ≦ 0.3, 0.1 ≦ y ≦ 0.4, 0.6 ≦ z ≦ 0.8, 0 ≦ t ≦ 0.1, 0 ≦ a ≦ 0.5, M is one or more additive elements selected from Mg, Ca, Al, Ti, V, Cr, Zr, Nb, Mo, and W) A method for producing nickel cobalt manganese composite hydroxide particles represented by:
In an oxygen-containing gas atmosphere, a mixed aqueous solution containing a metal compound containing nickel, a metal compound containing cobalt, and a metal compound containing manganese is mixed with an initial aqueous solution containing an alkaline aqueous solution to form a reaction aqueous solution. The manufacturing method of the nickel cobalt manganese composite hydroxide particle which has a crystallization process.   The method for producing nickel cobalt manganese composite hydroxide particles according to claim 2, wherein the ammonium ion concentration in the initial aqueous solution and in the reaction aqueous solution is 0 or more and 15 g / L or less.   The method for producing nickel cobalt manganese composite hydroxide particles according to claim 2 or 3, wherein the temperature of the reaction aqueous solution is maintained at 30C or higher and 50C or lower during the crystallization step.   The nickel cobalt manganese composite hydroxide particles according to any one of claims 2 to 4, further comprising a coating step of coating the nickel cobalt manganese composite hydroxide particles obtained in the crystallization step with the additive element. Manufacturing method. In the coating step, a method of coating the nickel cobalt manganese composite hydroxide particles with the additive element,
An aqueous solution containing the additive element is added to a liquid in which the pH-controlled nickel cobalt manganese composite hydroxide particles are suspended, and the additive element is deposited on the surface of the nickel cobalt manganese composite hydroxide particles. Method,
A method of spray drying a slurry in which the nickel cobalt manganese composite hydroxide particles and the compound containing the additive element are suspended;
A method of mixing the nickel cobalt manganese composite hydroxide particles and the compound containing the additive element by a solid phase method,
The method for producing nickel-cobalt-manganese composite hydroxide particles according to claim 5, which is any one of the above methods. General formula: Li _{1 + α} Ni _x Co _y Mn _z M _t O ₂ (0.25 ≦ α ≦ 0.55, x + y + z + t = 1, 0.05 ≦ x ≦ 0.3, 0.1 ≦ y ≦ 0. 4, 0.6 ≦ z ≦ 0.8, 0 ≦ t ≦ 0.1, M is an additive element, and is selected from Mg, Ca, Al, Ti, V, Cr, Zr, Nb, Mo, and W Lithium metal composite oxide particles represented by one or more elements,
The lithium metal composite oxide particles, wherein the secondary particles of the lithium metal composite oxide particles are porous particles, and the porosity inside the secondary particles is 10% or more and 30% or less. The lithium metal composite oxide particles according to claim 7, which has a specific surface area of 3.0 m ² / g or more.   The lithium metal composite oxide particles according to claim 7 or 8, wherein the tap density is 1.6 g / cc or more.   10. The discharge capacity under a high discharge rate condition (2C) of a non-aqueous electrolyte secondary battery using the lithium metal composite oxide particles as a positive electrode material is 200 mAh / g or more. The lithium metal composite oxide particles according to Item.